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-   -   making periodicity in Stationar in Fluent under multiple reference frame (mrf) (https://www.cfd-online.com/Forums/fluent/158568-making-periodicity-stationar-fluent-under-multiple-reference-frame-mrf.html)

Hybrid August 28, 2015 11:17
making periodicity in Stationar in Fluent under multiple reference frame (mrf)
 
Hi,

I am trying to simulate a rotor in hovering. To make mesh size small, I wish to use periodic BCs.

In MRF, two fluid zones are defined:

1: Moving Zone (make periodic zones are successful)
2: Stationary Zone ( making periodic zones are unsuccessful)

How can I make zones periodic in the Stationary Fluid Zone?

Any help, suggestion, comment, plz?

Far August 28, 2015 13:23
Yes, you can make them periodic!!!

Hybrid August 28, 2015 20:18
How I can make periodic? It gives error.:
Failed to make zones periodic.
Error object: #f
Can you explain?

Mesh_Image

Far August 31, 2015 01:36
Hi.

I tried on both models and used three methods.

What I did was: (1st method) ---> sucessful

1. Made the zone rotation axis to Y axis

2. Change per2 and shad2 to interface

3. used interface panel and make the mesh periodic


2nd method (not successful):

1. Made the zone rotation axis to Y axis

2. Used these command. define > bc > mz > mp > select pair of periodic surfaces

3rd method: (not successful):

1. Rotate the model so that axis of rotation is Z axis.

2. Used these command. define > bc > mz > mp > select pair of periodic surfaces

3. Possible problem is that axis of rotation is not passing through center of periodic surfaces. You should do it in the meshing software.


Note: Why are you using 180 deg sector?

Hybrid August 31, 2015 01:43
I have two blades, so 180deg sector.
I used Ansys Meshing, in moving zone, periodic zone was successful.

I am sorry, not to tell you the rotation axis, i think (0.045, 0, 0).

Now I tried in Pointwise, periodic zones are successful but getting the error

Code:
  Periodic zone  7: average rotation angle (deg) = 180.000 (180.000 to 180.000)
                      stored zone rotation angle (deg)  = 180.000
                      stored axis  , (0.000000e+00, 1.000000e+00, 0.000000e+00)
                      stored origin, (4.500000e-02, 0.000000e+00, 0.000000e+00)
  Periodic zone  15: average rotation angle (deg) = 170.951 (-180.000 to 180.000)
                      stored zone rotation angle (deg)  = 180.000
                      stored axis  , (0.000000e+00, 1.000000e+00, 0.000000e+00)
                      stored origin, (4.500000e-02, 0.000000e+00, 0.000000e+00)
WARNING: rotation inconsistent on zone 15. Please check periodic setup.
Done.
I am sending you the case file at your email.

Far August 31, 2015 01:54
there is something wrong with origin parameters for the stater.

Can you make it periodic in gridgen?

Hybrid August 31, 2015 03:21
In gridgen, I cannot apply "Periodic BC" for fluent. I did this in fluent.

Hybrid September 16, 2015 10:08
Finally,

I am successful making zones periodic in Ansys Meshing by using Match Control and proper definition of Coordinates.

Job is done. Thanks for the help guys.


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